8.David invests 100 dollars in a stock. Each year his investment doubles in value with probability 0.4
and decreases in value by 50% with probability 0.6. What is the expected value of David's
investment after 20 years?
(A) 90
(B) 110
(C) 259
(D) 673
(E) 1745
【非選題】 V. Writing (10%)
Directions: The ROC Ministry of Foreign Affairs has hosted contests of recruiting
short clips filmed by talents full of creativity to communicate Taiwanese stories
through moving images for several years. If you were one of the contestants, what
“theme” and “stories” would you film to showcase Taiwan and raise the profile of
Taiwan abroad? Please write a paragraph to describe your idea.